Objective To explore the effects and mechanisms of human umbilical cord mesenchymal stem cell (HUC-MSC)-derived exosomes (Exo) pretreated with Huangkui capsules on renal ischemia-reperfusion injury (IRI). Methods HUC-MSCs were cultured in media containing different concentrations of Huangkui capsules for 24 hours to determine cell viability and select an appropriate concentration for subsequent experiments. HUC-MSCs were pretreated with 50 μg/mL Huangkui capsules for 24 hours, and Exo were extracted using an exosome extraction kit. The morphology was observed under a transmission electron microscope, particle size was measured by nanoparticle tracking analysis, and the expression of exosomal membrane surface marker proteins was detected by Western blot. Human renal tubular epithelial cells (HK-2 cells) were randomly divided into hypoxia/reoxygenation group (M group), hypoxia/reoxygenation + Exo group (E group), and hypoxia/reoxygenation + Huangkui capsules pretreated Exo group (H group). Western blotting was used to measure the expression of endoplasmic reticulum stress (ERS)-related proteins, and real-time fluorescent quantitative reverse transcription polymerase chain reaction was used to measure the expression of ERS-related gene messenger RNA (mRNA). Mice were randomly divided into sham operation group (Sham group), ischemia-reperfusion group (I/R group), ischemia-reperfusion + Exo group (E group), and ischemia-reperfusion + Huangkui capsules pretreated Exo group (H group). Renal histological assessment, serum creatinine (Scr), blood urea nitrogen (BUN) measurement and inflammatory factor detection were performed 24 hours later. Results Both Exo and Huangkui capsules prereated Exo had a bilayer membrane structure and a cup-shaped morphology; their average particle sizes were 116.8 nm and 81.3 nm, respectively. Both expressed CD9, CD63, TSG101. Compared with the M group, the E group had decreased relative expression of transcription factor 6 (ATF6) and protein kinase R-like endoplasmic reticulum kinase (PERK) proteins, increased mRNA relative expression, increased relative expression of C/EBP homologous protein (CHOP) protein, and decreased mRNA relative expression. Compared with the E group, the H group had decreased relative expression of ATF6, PERK, CHOP proteins, and decreased mRNA relative expression of ATF6 and PERK (all P<0.05). Animal experimental results showed that compared with the Sham group, the I/R group had increased renal tubular injury scores, Scr, BUN, interleukin (IL)-1β, IL-10, IL-18, tumor necrosis factor (TNF)-α levels. Compared with the I/R group, the E and H groups had decreased renal tubular injury scores and Scr, BUN, IL-1β, IL-10, IL-18, TNF-α levels. Compared with the E group, the H group had decreased renal tubular injury scores and Scr, BUN, IL-1β, IL-10, IL-18, TNF-α levels (all P<0.05). Conclusions Huangkui capsules pretreatment HUC-MSC-derived Exo may alleviate renal IRI by inhibiting ERS.

Objective To investigate the global burden of visceral leishmaniasis (VL) from 1990 to 2021 and predict the trends in the burden of VL from 2022 to 2035, so as to provide insights into global VL prevention and control. Methods The global age-standardized incidence, prevalence, mortality and disability-adjusted life years (DALYs) rates of VL and their 95% uncertainty intervals (UI) were captured from the Global Burden of Disease Study 2021 (GBD 2021) data resources. The trends in the global burden of VL were evaluated with average annual percent change (AAPC) and 95% confidence interval (CI) from 1990 to 2021, and gender-, age-, country-, geographical area- and socio-demographic index (SDI)-stratified burdens of VL were analyzed. The trends in the global burden of VL were projected with a Bayesian age-period-cohort (BAPC) model from 2022 to 2035, and the associations of age-standardized incidence, prevalence, mortality, and DALYs rates of VL with SDI levels were examined with a smoothing spline model. Results The global age-standardized incidence [AAPC = -0.25%, 95% CI: (-0.25%, -0.24%)], prevalence [AAPC = -0.06%, 95% CI: (-0.06%, -0.06%)], mortality [AAPC = -0.25%, 95% CI: (-0.25%, -0.24%)] and DALYs rates of VL [AAPC = -2.38%, 95% CI: (-2.44%, -2.33%)] all appeared a tendency towards a decline from 1990 to 2021, and the highest age-standardized incidence [2.55/10⁵, 95% UI: (1.49/10⁵, 4.07/10⁵)], prevalence [0.64/10⁵, 95% UI: (0.37/10⁵, 1.02/10⁵)], mortality [0.51/10⁵, 95% UI: (0, 1.80/10⁵)] and DALYs rates of VL [33.81/10⁵, 95% UI: (0.06/10⁵, 124.09/10⁵)] were seen in tropical Latin America in 2021. The global age-standardized incidence and prevalence of VL were both higher among men [0.57/10⁵, 95% UI: (0.45/10⁵, 0.72/10⁵); 0.14/10⁵, 95% UI: (0.11/10⁵, 0.18/10⁵)] than among women [0.27/10⁵, 95% UI: (0.21/10⁵, 0.33/10⁵); 0.06/10⁵, 95% UI: (0.05/10⁵, 0.08/10⁵)], and the highest mortality of VL was found among children under 5 years of age [0.24/10⁵, 95% UI: (0.08/10⁵, 0.66/10⁵)]. The age-standardized incidence (r = -0.483, P < 0.001), prevalence (r = -0.483, P < 0.001), mortality (r = -0.511, P < 0.001) and DALYs rates of VL (r = -0.514, P < 0.001) correlated negatively with SDI levels from 1990 to 2021. In addition, the global burden of VL was projected with the BAPC model to appear a tendency towards a decline from 2022 to 2035, and the age-standardized incidence, prevalence, mortality and DALYs rates were projected to be reduced to 0.11/10⁵, 0.03/10⁵, 0.02/10⁵ and 1.44/10⁵ in 2035, respectively. Conclusions Although the global burden of VL appeared an overall tendency towards a decline from 1990 to 2021, the burden of VL showed a tendency towards a rise in Central Asia and western sub-Saharan African areas. The age-standardized incidence and prevalence rates of VL were relatively higher among men, and the age-standardized mortality of VL was relatively higher among children under 5 years of age. The global burden of VL was projected to continue to decline from 2022 to 2035.

Objective To investigate the regulatory role of the programmed cell death protein 1 (PD-1) and its ligand programmed cell death protein ligand 1 (PD-L1) signaling on the subtypes and functions of natural killer (NK) cells at the maternal-fetal interface during the second trimester in mice following Toxoplasma gondii infection during the first trimester. Methods Twelve 6- to 8-week-old female mice of the C57BL/6J strain were divided into a control group and an infection group, of 6 mice in each group. On the 6.5th day of pregnancy (Gd6.5), each pregnant mouse in the infection group was intraperitoneally injected with 150 tachyzoites of the Toxoplasma gondii PRU strain, while mice in the control group were injected with an equal volume of physiological saline. On the 12.5th day of pregnancy (Gd12.5), uterus and placenta tissues were sampled from pregnant mice for pathological observations, and the mRNA expression levels of PD-1, PD-L1, and tumor necrosis factor-α (TNF-α) were quantified in uterus and placenta tissues. The PD-1 and DX5 expression was measured on NK cells at the maternal-fetal interface using flow cytometry. In addition, the in vitro JEG-3 trophoblast cells and NK-92MI cells co-culture system was established as the control group, and the addition of T. gondii tachyzoites in the co-culture system served as the infection group. The PD-1, PD-L1, and DX5 mRNA expression was quantified in cells using real-time fluorescence quantitative reverse transcription PCR (RT-qPCR) assay, and the TNF-α concentration was measured in the cell culture supernatant using enzyme-linked immunosorbent assay (ELISA). Results On Gd12.5, clear and intact cellular structures of placental decidual tissues were seen in pregnant mice in the control group, with no remarkable abnormal changes found in the uterine columnar epithelial cells, and inflammatory cell infiltration and blood stasis at varying degrees were found in uterine and placental tissues from pregnant mice in the infection group. The relative PD-1, PD-L1, and TNF-α mRNA expression was (1.004 ± 0.004), (1.001 ± 0.001), and (1.001 ± 0.001) in uterine tissues from pregnant mice in the control group and (2.480 ± 0.720), (3.355 ± 0.920), and (2.391 ± 0.073) in the infection group, respectively. The relative PD-1, PD-L1, and TNF-α mRNA expression was (1.007 ± 0.010), (1.006 ± 0.006), and (1.001 ± 0.001) in the uterine tissues in the control group and (6.948 ± 1.918), (3.225 ± 1.034), and (1.536 ± 0.150) in the infection group, respectively. The relative PD-1, PD-L1, and TNF-α mRNA expression was higher in both the uterine (t = 3.55, 4.43 and 33.02, all P values < 0.05) and placental tissues (t = 5.36, 3.72 and 6.18, all P values < 0.05) in the infection group than in the control group. Flow cytometry showed that the proportions of PD-1⁺ NK cells, PD-1⁺ DX5⁺ NK cells, and DX5⁺ NK cells were (12.200 ± 1.082)%, (9.373 ± 7.728)%, and (44.000 ± 4.095)% in uterine tissues from pregnant mice in the control group, and (21.733 ± 1.630)%, (18.767 ± 1.242)%, and (73.367 ± 0.611)% in the infection group, respectively. The proportions of PD-1⁺ NK cells, PD-1⁺ DX5⁺ NK cells, and DX5⁺ NK cells were (1.100 ± 0.510)%, (2.277 ± 1.337)%, and (96.167 ± 2.831)% in placental tissues from mice in the control group, and (26.867 ± 9.722)%, (23.433 ± 6.983)%, and (82.467 ± 2.248)% in the infection group, respectively. The proportions of PD-1⁺ NK cells (t = 8.45, P < 0.05) and DX5⁺ NK cells (t = 12.29, P < 0.05) were higher in uterine tissues from pregnant mice in the infection group than in the control group, and no significant difference was seen in the proportion of PD-1⁺ DX5⁺ NK cells (Z = -1.09, P > 0.05). The proportions of PD-1⁺ NK cells (t = 4.58, P < 0.05) and PD-1⁺ DX5⁺ NK cells (t = 5.15, P < 0.05) were higher in placental tissues from pregnant mice in the infection group than in the control group, while the proportion of DX5⁺ NK cells was lower in the infection group than in the control group (t = -6.56, P < 0.05). RT-qPCR assay revealed that the relative PD-1, PD-L1, and DX5 mRNA expression was (1.010 ± 0.005), (1.002 ± 0.003), and (1.001 ± 0.001) in the JEG-3 cells and NK92MI cells co-culture system and (3.638 ± 1.258), (0.397 ± 0.158), and (4.267 ± 1.750) in the control group, and ELISA measured that the TNF-α concentration was higher in the cell culture supernatant in the infection group [(22.056 ± 3.205) pg/mL] than in the control group [(12.441 ± 0.001) pg/mL] (t = 5.20, P < 0.05). The PD-1(t = 3.62, P < 0.05) and DX5 mRNA expression (t = 3.23, P < 0.05) was higher in the infection group than in the control group, and the PD-L1 mRNA expression was lower in the infection group than in the control group (t = -6.63, P < 0.05). Conclusions Following T. gondii infection, both PD-L1 expression and PD-1 expression on DX5⁺ NK cells at the maternal-fetal interface are upregulated in mice during the second trimester; however, the proportion of DX5⁺ NK cells decreases. These findings suggest that PD-1/PD-L1 signaling may suppress NK cell functions by modulating DX5⁺ NK cell subsets.

This study employed the "disease-medicine-dose" pattern to mine the medication rules of traditional Chinese medicine(TCM) prescriptions containing Astragali Radix in ancient Chinese medical books, aiming to provide a scientific basis for the clinical application of Astragali Radix and the development of new medicines. The TCM prescriptions containing Astragali Radix were retrieved from databases such as Chinese Medical Dictionary and imported into Excel 2020 to construct the prescription library. Statical analysis were performed for the prescriptions regarding the indications, syndromes, medicine use frequency, herb effects, nature and taste, meridian tropism, dosage forms, and dose. SPSS statistics 26.0 and IBM SPSS Modeler 18.0 were used for association rules analysis and cluster analysis. A total of 2 297 prescriptions containing Astragali Radix were collected, involving 233 indications, among which sore and ulcer, consumptive disease, sweating disorder, and apoplexy had high frequency(>25), and their syndromes were mainly Qi and blood deficiency, Qi and blood deficiency, Yin and Yang deficiency, and Qi deficiency and collateral obstruction, respectively. In the prescriptions, 98 medicines were used with the frequency >25 and they mainly included Qi-tonifying medicines and blood-tonifying medicines. Glycyrrhizae Radix et Rhizoma, Angelicae Sinensis Radix, Ginseng Radix et Rhizoma, Atractylodis Macrocephalae Rhizoma, and Citri Reticulatae Pericarpium were frequently used. The medicines with high frequency mainly have warm or cold nature, and sweet, pungent, or bitter taste, with tropism to spleen, lung, heart, liver, and kidney meridians. In the treatment of sore and ulcer, Astragali Radix was mainly used with the dose of 3.73 g and combined with Glycyrrhizae Radix et Rhizoma to promote granulation and heal up sores. In the treatment of consumptive disease, Astragali Radix was mainly used with the dose of 37.30 g and combined with Ginseng Radix et Rhizoma to tonify deficiency and replenish Qi. In the treatment of sweating disorder, Astragali Radix was mainly used with the dose of 3.73 g and combined with Glycyrrhizae Radix et Rhizoma to consolidate exterior and stop sweating. In the treatment of apoplexy, Astragali Radix was mainly used with the dose of 7.46 g and combined with Glycyrrhizae Radix et Rhizoma to dispell wind and stop convulsions. Astragali Radix can be used in the treatment of multiple system diseases, with the effects of tonifying Qi and ascending Yang, consolidating exterior and stopping sweating, and expressing toxin and promoting granulation. According to the manifestations of different diseases, when combined with other medicines, Astragali Radix was endowed with the effects of promoting granulation and healing up sores, tonifying deficiency and Qi, consolidating exterior and stopping sweating, and dispelling wind and replenishing Qi. The findings provide a theoretical reference and a scientific basis for the clinical application of Astragali Radix and the development of new medicines.
Drugs, Chinese Herbal/history* ; Humans ; Medicine, Chinese Traditional/history* ; History, Ancient ; Astragalus Plant/chemistry* ; China ; Astragalus propinquus

Objective To compare the long-term prognosis differences between surgical radical resection and endoscopic resection for early gastric cancer patients based on the SEER database. Methods A total of 1 437 patients with stage Tis to T_1b gastric adenocarcinoma were selected from the SEER database from January 1, 2004 to December 31, 2013. They were divided into a surgery group (n=1 257) and an endoscope group (n=180) according to the treatment method. Kaplan-Meier survival curve and Cox regression model were used to analyze survival outcomes. Results The patients in the surgery group were younger than those in the endoscope group ([67.63±12.97] years old vs [71.29±10.82] years old), with higher rates of T₁ stage (97.45% vs 87.78%) and lymph node metastasis (19.73% vs 5.00%, all P＜0.001). The median follow-up time for all patients was 37 (15, 66) months, and the mortality rate of gastric cancer in the endoscope group was lower than that in the surgery group (23.33% vs 27.13%, P＜0.001). Univariate Cox analysis showed that treatment modality, age, sex, T stage, lymph node metastasis were all associated with early gastric cancer mortality (all P＜0.05), and the risk of death in the endoscope group was 43% of that in the surgery group (HR=0.43, P=0.015). After adjusting for multiple factors, there was no statistically significant difference in mortality risk between the two groups (P=0.067), but after excluding lymph node positive patients, the mortality risk in the endoscope group was 46% of that in the surgery group (HR=0.46, P=0.048). Conclusions For early gastric cancer patients with negative lymph nodes, endoscopic resection may provide better survival benefits than surgical procedures, suggesting that it can be the preferred treatment strategy for patients with low risk of lymph node metastasis.

Objective To evaluate the pharmacokinetic characteristics and safety of single and multiple oral azvudine tablets in healthy young and elderly Chinese subjects.Methods This was a open-label and parallel-group study.The trial consisted of two groups:healthy young subjects group and healthy elderly subjects group,with 12 subjects in each group.Enrolled subjects were first given a single dose,fasting oral azvudine tablet 5 mg,after a 3-day cleansing period entered the multiple dose phase,fasting oral azvudine tablet 5 mg·d-1 for 7 days.Results After a single dose of azvudine 5 mg,Cmax and AUC0-∞ were(4.76±2.12)ng·mL-1,(6.53±2.20)ng·mL-1·h,and Tmax,t1/2 were 0.75,1.87 h in young subjects;Cmax and AUC0-∞ were(6.40±3.25)ng·mL-1,(9.50±3.70)ng·mL-1·h,and Tmax,t1/2 were 0.63,2.66 h in elderly subjects.After a multiple dose of azvudine 5 mg·d-1 for 7 d,Cmax and AUC0-∞ were(3.26±1.61)ng·mL-1,(5.38±2.19)ng·mL-1·h,and Tmax,ss,t1/2,ss were 0.88,2.13 h in young subjects;Cmax,ss and AUC0-∞,ss were(3.97±2.09)ng·mL-1,(6.71±3.26)ng·mL-1·h,and Tmax,ss,t1/2,ss were 0.75,2.56 h in elderly subjects.Elderly/young geometric mean ratios and 90％CIs were 128.37％(88.23％-186.76％),139.93％(105.42％-185.72％),140.03％(106.33％-184.41％)for azvudine Cmax,AUC0-t,AUC0-∞ after a single dose,and were 118.66％(80.83％-174.20％),118.41％(83.60％-167.69％),118.95％(84.78％-166.89％)for azvudine Cmax,AUC0-t,AUC0_∞ after a multiple dose of azvudine 5 mg·d-1 for 7 d.Conclusion After single and multiple oral administration of azvudine tablets,systemic exposure to azvudine was higher in healthy elderly subjects compared with healthy young subjects.After taking azvudine tablets,the types,severity and incidence of adverse events and adverse drug reactions in healthy elderly people were not significantly different from those in healthy young subjects.Azvudine was found to be safe and well tolerated in healthy elderly subjects.

Objective To explore the potential mechanism of action of paeoniflorin in diabetes mellitus,the related targets and pathways were preliminarily discussed,based on the network pharmacology and molecular docking technology.Methods Analyze the potential targets of paeoniflorin using the Swiss Target Prediction database.Genecards and OMIM databases yielded the genes of diabetes-related illnesses.After taking the intersection of the two,protein-protein interaction network(PPI)was established using STRING and Cytoscape programs to search for key genes with strong correlation and complete gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Use AutoDockTools and Pymol programs to complete protein molecule docking validation.Results The pharmacologically-related study revealed 63 targets associated with paeoniflorin,4 758 genes related to diabetes,and 50 intersection targets.15 key genes including vascular endothelial growth factor A(VEGFA),epidermal growth factor receptor(EGFR),V-Ha-ras harvey(HRAS),V-src sarcoma(SRC)and heat shock protein hs 90-alpha(HSP90AA1)were screened.RAs-associated protein 1,Ras,calcium and other signaling pathways were obtained by KEGG pathway analysis.Molecular docking results showed that paeoniflorin had good binding ability with key genes.Conclusion Paeoniflorin can treat diabetes through multiple targets and pathways,and this mechanism can provide a basis for the application of paeoniflorin in anti diabetes and drug research and development.

Objective To isolate the Japanese encephalitis virus carried by Culex tritaeniorhynchus in Dongchuan District of Yunnan Province and analyze its molecular characteristics, so as to provide insights into the prevention and control of Japanese encephalitis in Yunnan Province. Methods Mosquito specimens were collected using mosquito-trapping lamps from pig farms in Batang Village and Xiaoxin Village, Dongchuan District, Kunming City, Yunnan Province in July 2016, and the mosquito species was identified according to the mosquito morphology. Then, 60 to 100 mosquitoes of each species served as a group and were ground. Baby hamster kidney-21 (BHK-21) cells and Aedes albopictus clone C6/36 cells were used for virus isolation, and positive isolates were identified using flavivirus primers. The positive isolates were amplified using reverse transcription polymerase chain reaction (RT-PCR) assay with 15 pairs of specific primers covering the full length of the genotype I Japanese encephalitis virus, and DNA sequence assembly was performed using the software SeqMan in the DNASTAR package. The obtained sequences were aligned with the complete sequences of 38 Japanese encephalitis virus downloaded from the GenBank with the software MegAlign, and the nucleotide and amino acid homology analyses of the obtained sequences were performed. The difference in amino acid sites was analyzed with the software GeneDoc, and phylogenetic trees were created based on the sequences of the coding region and E protein of the isolated Japanese encephalitis virus with the software Mega X. In addition, the secondary and tertiary structures of the E protein of the Japanese encephalitis virus were predicted using the online tool SOPMA and the software Swiss-Model. Results A total of 5 820 mosquitoes were collected and 3 843 Cx. tritaeniorhynchus (66.03%) were identified according to the mosquito morphology. A positive virus isolate, termed YNDC55-33, was isolated from Cx. tritaeniorhynchoides following batches of virus isolation from mosquito specimens, and cytopathic effect was observed following inoculation into BHK-21 and C6/36 cells. The YNDC55-33 virus isolate was successfully amplified with the flavivirus primes, and a long sequence containing 300 nucleotides was obtained. Following sequence alignment using the BLAST tool, the sequence of the YNDC55-33 virus isolate had high homology with that of the genotype I Japanese encephalitis virus. A long sequence with 10 845 nucleotides in length, which encoded 3 432 amino acids, was obtained by splicing the full sequence of the YNDC55-33 virus isolate. Phylogenetic analysis based on the whole-genome sequence and E gene sequence of the YNDC55-33 virus isolate showed that the new YNDC55-33 virus isolate was most closely related to the genotype I Guizhou isolate (GenBank accession number: HM366552), with nucleotide homology of 98.5% and amino acid homology of 99.4%, and the YNDC55-33 virus isolate shared 97.96% ± 0.33% nucleotide homology and 99.35% ± 0.08% amino acid homology with other genotype I Japanese encephalitis virus isolates, and < 90% nucleotide homology and < 98% amino acid homology with other genotypes of Japanese encephalitis virus. The YNDC55-33 virus isolate and the live attenuated virus vaccine candidate SA14-14-2 isolate differed at 16 amino acid sites on E gene, and 7 out of 8 key amino acid sites related to neurovirulence. The secondary and tertiary structures of the E protein of the YNDC55-33 virus isolate were predicted to be characterized by random coils. Conclusions A genotype I Japanese encephalitis virus was isolated from Cx. tritaeniorhynchus in Dongchuan District, Kunming City. This virus isolate and the live attenuated virus vaccine candidate SA14-14-2 isolate does not differ at antigenic epitopes-related key amino acid sites, and the major protein structure of the virus isolate is random coils. This study adds new data for the epidemiological distribution of Japanese encephalitis virus in Yunnan Province, which may provide insights into the prevention and control of Japanese encephalitis in the province.

Objective To examine the impact of arid climates on distribution of Oncomelania hupensis snails in the Poyang Lake area, so as to provide insights into precision control of O. hupensis snails in the Poyang Lake area. Methods O. hupensis snails-infested grass islands in Hukou County, Lianxi District and Lushan City in the northern Poyang Lake area, and Jinxian County, Nanchang County and Poyang County in the southern Poyang Lake area were selected as the study areas, and the occurrence of frames with living snails and the mean density of living snails were captured from snail surveys in the study areas in spring and autumn each year from 2006 to 2023. Five years 2007, 2011, 2013, 2019 and 2022 were selected as drought years, and the mean daily water levels were collected at the Xingzi hydrological station in the drought years, normal flow year (2012) and flood year (2020). The numbers of days with water levels ranging from the lower elevation (11 m) to the upper elevation (16 m) for snail survival and the numbers of days with water levels of 11 m and below were collected in the Poyang Lake area, and the changes of snail indicators were compared in different grass islands in the Poyang Lake area before and after drought. Results The numbers of days with water levels ranging from 11 to 16 m were 110, 88, 136 d and 125 d at the Xingzi hydrological station in four drought years 2007, 2011, 2013 and 2019, which were less than in the flow year and flood year, and the days with water levels of 11 m and below were 242, 277, 220 d and 198 d in four drought years 2007, 2011, 2013 and 2019, which were longer than in the flow year and flood year. A total of 416 snails-infested marshlands were surveyed in the Poyang Lake area from 2006 to 2021, and the survey marshlands accounted for 43.12% (307/712) and 46.98% (109/232) of total marshlands in the southern and northern Poyang Lake areas, respectively. The median occurrence of frames with living snails and mean density of living snails were 0.60% (interquartile range, 4.04%) and 0.010 1 snail/0.1 m² (interquartile range, 0.076 1 snail/0.1 m²) in drought years, which were both lower than those [1.33% (5.19%) and 0.022 8 (0.098 9) snail/0.1 m²] in non-drought years (χ²= 42.170 and 44.911, both P values < 0.01). The proportion of grass islands with a continuous decline in snail indicators was higher in the southern Poyang Lake area than in the northern Poyang Lake area after the next year of drought (24.24% vs. 2.33%; χ² = 10.633, P < 0.01), and the proportion of grass islands with rebounding snail indicators was higher in the northern Poyang Lake area than in the southern Poyang Lake area (53.49% vs. 15.76%; χ² = 26.966, P < 0.01). A longitudinal analysis of snail indicators in marshlands with rebounding snail indicators after drought showed 1 to 5 years for return to pre-drought snail status, with a median of 2 (interquartile range, 1) years, and snail status was more likely to rebound if the occurrence of frames with living snails and the mean density of living snails were 2.11% and 0.025 5 snail/0.1 m² and greater in snails-infested grass islands. Conclusions Drought causes a remarkable decline in O. hupensis snail indicators in the Poyang Lake area, with a more remarkable impact in the southern Poyang Lake area, and 1 to 5 years are required for return to pre-drought snail status.

This study constructed a LHCGR-CRE-luc-HEK293 transgenic cell line according to the activation of the cAMP signaling pathway after recombinant human chorionic gonadotropin binding to the receptor. The biological activity of recombinant human chorionic gonadotropin was assayed using a luciferase assay system. The relative potency of the samples was calculated using four-parameter model. And the method conditions were optimized to validate the specificity, relative accuracy, precision and linearity of the method. The results showed that there was a quantitative potency relationship of human chorinonic gonadotropin (hCG) in the method and it was in accordance with the four-parameter curve. After optimization, the conditions were determined as hCG dilution concentration of 2.5 μg·mL^-1, dilution ratio of 1∶4, cell number of 10 000-15 000 cells/well, and induction time of 6 h. The method had good specificity, relative accuracy with relative bias ranging from -8.9% to 3.4%, linear regression equation correlation coefficient of 0.996, intermediate precision geometric coefficient of variation ranging from 3.3% to 15.0%, and linearity range of 50% to 200%. This study successfully established and validated a reporter gene method to detect hCG biological activity, which can be used for hCG biological activity assay and quality control.